Fluid pressure servomotor



July 22, 1952 G. G. NAUD 7 FLUID PRESSURE SERVOMOTOR Filed April 17, 1946 e Sheets-Sheet 2 mmvroa. George G. Naaa ATTORNEY:

Jul} 22,1952 5, NAUD 2,604,075

FLUID PRESSURE SERVOMOTOR Filed April 17, 1946 6 Sheets-Sheet 3 ATTORNEY.

y 22, 1952 G. G. NAUD 2,604,075

I FLUID PRESSURE SERVOMOTOR Filed April 17, 1946 6 Sheets-Sheet 4 INVENTOR. George G. Naud ATTORIVEY July 22, 1952 G. G. NAUD FLUID PRESSURE SERVOMOTOR Filed April 17, 1946 6 Sheets-Sheet 6 mmvron. George G. Naud av g & A 1012mm.-

Patented July 22 11952 UNITED STATES PATENT OFFICE" FLUID PRESSURE SERVOMOTOR George vG. Naud, Seattle, Wash.

Application April 17, 1946, Serial No. 662,745

7 Claims. (Cl. 121- 38) This invention relates to pressure fluid servomotors and aims primarily to provide a novel pressure fluid servo-motor especially designed and particularly adapted for use and application in the shifting of single-acting and double-acting clutches; in the shifting of power transmission reverse gears; and in various other power appliances and mechanisms, wherein positional change of an element or member thereof is desired or required.

Another object of the invention is to provide a pressure fluid servo-motor adapted for both electrical and manual operation.

A further object is to provide a pressure fluid servo-motor adapted to be actuated from either a local or a remote station or stations, or both.

A still further object is to provide a pressure fluid servo-motor, wherein the force or drawbar pull exerted thereby and the speed of operation thereof are selectively adjusted and controlled to obtain the desired operating condition.

A still further object is to provide a pressure fluid servo-motor adaptable and capable of imparting shifting movement in either full or partial degree.

A still further object is to provide a pressure fluid servo-motor having an adjustable neutral position or positive stop, at a selective point or positionintermediate its path of travel, which neutral position is especially desirable in the shiftingof double-acting or twin clutches, and the like.

Astill further object is to provide a pressure fluid servo-motor embodying a novel multi-switch control for actuating the same.

A still further object is to provide a pressure fluid servo-motor embodying novel cam actuated adjustable limit switches operable in timed sequence during shifting movements of the same, whereby partial shifting movements of positive duration are obtained.

A still further object is to provide a pressure fluid servo-motor having operating controls which are readily accessible for adjustment and/ or replacement.

Still further objects are to provide either a two-way or three-way pressure fluid servo-motor, which is a complete self-contained compact unit; which is flexible and smooth in operation; and which has a positive controlled action.

The above, and additional objects which will hereinafter be more specifically treated are attained by such means as areshown in the accompanying drawings, described in the following specification and then more clearly pointed out in the claims. which are appended hereto and form part of the specification.

. cam: rod and adjustable limit switchesfofsam'e With reference to the drawings, in whichthere are illustrated several embodiments of the invention, and throughout the several views of which like characters of reference designate similar parts: I s

Figure 1 is a side elevation of the two-way pressure fluid servo-motor, comprehended by the present invention, which is shown in its retracted position, and as it would appear when operatively connected to the shifting lever of a single-acting clutch schematically illustrated therein;

Figure 2 is an end elevation of the two-way pressure fluid servo-motor, taken at the line 2-2 of Fig. 1;

Figure 3 is a top plan view of the same taken,

at the line 3-3 of Fig. 1;

Figure 4 is a vertical longitudinal section taken on the line 44 of Fig. 3; l

Figures 5, 6, 7, 8 and 9 are vertical transverse sections taken, respectively, on the lines 5-5, 66, l'1, 88, and 9--9 of Fig. 4;

Figure 10 is a vertical longitudinal medial section, partially in side elevation, of the solenoid actuated piston control valve of the servo-motor, with the solenoid armature and valve piston shown in position for effecting clutch engagement;

Figure 11 is a similar view of the solenoid actuated piston control valve, with the solenoid armature and valve piston shown in position for efiecting clutch disengagement;

Figure 12 is an inverted fragmentary horizontal section taken on the line I2-l2 'of'Fig. 11;

Figure 13 is a diagrammatic view of the electrical circuits of the two-way pressure fluid servoposition, and as it would appear when operatively connected to the shifting lever of a double-acting clutch schematicallyillustrated therein; I

Figure 15 is an end elevation of the three-way pressure fluid servo-motor taken at the line.

15-45 ofFig. l6;

Figure 16 is an enlarged view in sideelevation of the three-way servo-motor, as it would appear in its fully retracted or reverse clutch engaging position;

Figure 17 is a horizontal section taken on the,

line 11-41 of Fi 16; a Figure 18 is an enlarged fragmentary. vertical transverse section taken on the line 18-48 of Fig.16;

Figure 19 is an enlarged fragmentary side elevation of the servo-motorwith the adjustable 3 illustrated their neutral or clutch disengaged position;

Fig. 20 is a similar view with the adjustable camrod and adjustable limit switches of the servo-motor illustrated in their forward clutch engaged position, and

Figure 21 is a diagrammatic view of the electrical circuits of the three-way pressure fluid servo-motor, with the adjustable cam rod and adjustable limit switches of same shown in dotted lines in a reverse clutch engaging position.

In the present disclosure, I have elected to show and describe the two-way and three-way pressure fluid servo-motors of the instant invention, as operatively connected to engine clutches. However, it is to be understood that this is for purposes of illustration only.

In Figures 1 to 13, inclusive, the numeral 30 designates the power take-off end of a power unit, such as an internal combustion engine, said unit being equipped with a single-acting or nonreversing clutch 3| having a clutch shifting or control lever 32, to which is operatively and pivotally connected, at a point intermediate its length, as by a pivot pin 33, the two-way pressure fluidservo-motor '34 of the present invention.

The two-way pressure fluid servo-motor 34, in the present instance, is preferably mounted upon the upper end of a pedestal or other suitable support 35, with the trunnion brackets 36 of the shifting apparatus disposed upon said upper end in opposed and aligned spaced rela tion and fixedly secured thereto by studs or bolts 31.

The numeral 38' designates the pneumaticpower cylinder of the shifting apparatus, provided with an-integrally closed end and an open end,

which latter is normally closed by a bossed end cover or head 39 fixedly secured to the cylinder end by cap screws 40. Integrally formed upon, or otherwise fixedly secured to, opposite sides of the cylinder 38,-at a point intermediate thel ength of the same, are axially aligned "-tru-nnions 4|, whereby the cylinder 38 is journalled or mounted for oscillative movement in the trunnion brackets 36 "to compensate for the arcuate path of travel qfithe ipivot pin 33, as will be readily apparent and understood by referring to -'l, and as will hereinafter be more fully described, Exteriorly formedupon the upper wall'portion'of the cyli-nder 38, substantially midway the length thereof, and extending upwardly therefrom in a radial relation thereto, is an integral rectangular boss or extension 42 terminating at its upper end in a rectangular flange '43. {Similarly "formed upon sjaid lppergwall portion and extending from the ends of the rectangular boss 42 to the ends of v the cylinder-38 are centrally and longitudinally disposed integral ribs 44,-whichare substantially semi-circular in cross-section, see Fig. "5, and formed within said ribs are pressure fluid passageways communicating at-their outer downwardly curved ends with their correlated-ends of cylinder-38 and at their-inner-upwardly curved w th e ic l y is s P e e-flu d Ports 46 formed within the rectangular boss 62 in spaced parallel relation, said ports. 46 at their upper ends having their side portions outwardly flared, as at 4], for a purpose'hereinafter'made more apparent.

Disposed for reciprocation within'the cylinder 38. a istpn 4.8 a a ed, to be fixedly S u to 'orinounted upon the inner shoulder terminal uqlfii h Of a. ii stq -fmd 4 which la te ext nds outwardly through and is guidedby "the bossed in fixed longitudinal spaced relation upon said end cover 39 of the cylinder 38, said piston rod at its outer end having a bifurcated member or yoke 50 threadedly secured thereto and adapted to straddle the clutch control lever 32 and to be pivotally connected thereto by the pivot pin 33. While the piston 48 may be of any desired construction, I prefer to employ the Well-known flexible cup type of pistongenerally-employed in pressure fluid cylinders, said piston, in the present instance, consisting of oppositely disposed cups 5|, fabricated from leather, or other suitable material, which cups are maintained in back to back spaced relation by a spacer washer 5-2 and bossed washers 53 and 54, the last mentioned bossed Washer 54 being threadedly engaged on the terminal threaded portion of the piston rod 49 and being positively secured in such threaded engagement, as by a headless set screw 55. To effectually prevent leakage of pressure fluid between the bossed end cover 39 and-the- The'numeral 51 generally designates a solenoid or electromagnetically actuated piston valve for controlling the flow of pressure fluid to the power cylinder 38 and the exhaust of the same therefrom, said piston valve having a cylindrical valve body- 58 exteriorly provided upon its lower or bottom cylindrical wall and substantially midway the length thereof with a rectangular flange 59 adapted to seat in sealed relation upon the corresponding rectangular flange 43 of said-power cylinder, and to be fixedly secured thereto by cap screws 60. Formed within the valve body 53 is a cylindrical bore GI and extending coaxially from the ends of said bore to the correlated ends of said valve body are counterbores 62. The numeral 63 designates transversely dis posed rows of apertures formed in longitudinal spaced relation within the rectangular flange portion 59 of the valve body 58 adjacent each-end of the bore 6| for establishing communication between said bore 6| and the pressure fluid ports 46 of the rectangular boss 42, which apertures are preferably of relatively small diameter, in order to prevent or minimize cutting of orundue wear upon the valve piston cups, presently to be described, and also to restrict or slow the flow of pressure fluid to the cylinder 38 and the be mounted upon and fixedly secured to the inner shouldered terminal portion of a piston rod or stem 61, said piston consisting'o'f oppo--' sitely disposed flexible cups 68, fabricated from any suitable material, which cups are maintained shouldered terminal portion by an intermediate spacer sleeve 69 and bossed end washers Ill and H, said last mentioned washer "II being threadedly-engagedupon the threaded terminal of'the' piston rod 61, as shown in Fig. 4. The flexible cups 68 are positionally spaced or located upon the piston rod 6'! in such a manner that when the piston; 86 is in its neutral or normally inac'tiv'emidposition, as shown'in Fig. 4, said cups 68 are positioned contiguous-to their correlated transverse row of --apertures'63, but are inter; mediate the latter andthe-pressure fluid inletv port-64, thus cutting off communication with the same, while establishing communication between said apertures 53 and the pressure fluid-exhaust peripheral edge portion thereof, and similarly seating within the other counterbore 62 and abutting the bossed end disk -'II and also axially slidable within said counterbore is a disk or spring seat I4 also having peripheral notches or slots 15, saiddisks 12 and I4 being notched as herein shown and described, in order to provide and maintain communication, at all times, between the bore BI and'the counterbores 62, and thereby.

positively insure of complete exhaustion of pressure fluid between the ports 48 and the exhaust ports 65, following each movement of the power piston 48, as willbe manifest and apparentby referring to Figs. 4, and 11.

'Integrally formed upon one end of the valve body 58 is a solenoid supporting flange 10 having a'c'entering boss 11 formed upon its face adapted to'receive in concentric seated relation thereon the inner end of a cylindrical solenoid casing I8, which latter is fixedly secured to the flange I6 by'machine screws 19' and extends outwardly therefrom in axial prolongation thereto, said solenoid casing I8 at its cpen'outer end having an annular shoulder 80 for a purpose, now to be described. snugly fitting within the solenoid casing I8 are inwardly bossed and .centrally apertured end pole pieces BI and 82, respectively, and an'ann'ular centerpole'piece 83, said-end pole piece 8| being adapted to abut or seat upon the annular shoulder 80, while the end pole piece 82 isadapted to abut the face of: the. solenoid supporting flangeIB. The numeral .84 designates a concentrically disposed tubular armature,

guide, the ends of which receive and snugly fit upon the inwardly bossed portions of the end pole pieces 8! and 82, and upon which,;mldway its length,the center pole pieoe'83 is mounted. Wound upon the armatureguide 84, intermediate the end pole pieces'8l and 82 and center pole piece 83-areysolenoid coils 85 and 86, the peripheral surfaces of which also snugly fit within the solenoid casing I8. Y v

- Reciprocatively disposed within the tubular guide 84 is an armature 81, one end of which is adapted to receive and threadedly engage the outer shouldered terminal portion. of the piston rod or'stem 61, which latter, extends through the 'endpole piece-'82 to effect such connection,

while the opposite end of the armature 81 is adapted to receive and threadedly. engage the inner'shouldered terminal portion .of a knurled stem 88, which extends through the vend'pole piece 8i for effecting manual operation, of the piston valve 66, when and asdesired. .Tosubstantially minimize or eliminate magneticadhesionbetween the end pole pieces 8| and 02 and the endsoi the armature 81, when the latter is' at either'end of its travel, said armature is provided upon its ends with centrally perforated disks 89 01 non-ferrous ornon-magnetic .ma-. 7;;

terial, which are positively retained-m..abutment-. with the endsof the armature 8'Iby the "shoulders 5' knurled stem 88,

of the piston rod 61 and the as shown in Fig. 4.

By. referring to Figs; 4,

counterbore 62 at the opposite end of the valve the cover 90 are helical compression springs 92 for balancing the piston 66 and returning the same to its neutral position when the solenoid coils and 86 havebeen de-energized.

Connected to the pressure fluid inlet orsupply port 64 by a pipe nipple 93 is a cross or, fourway fitting 94, to one side of which is.connected,. by a pipe elbow 95, a pressure gauge 96,. and; connected to the opposite side of said-fitting.

94, by pipe nipples 91 and a pipe elbow -98 is a pressure fluid reducing and regulatingvalve 99, to the inlet .end of which is connected, by a pipe nipple I00, a pressure fluid volume regulating angle valve IOI, which latter valve is con-,

nected by a hose I02 to a source of pressure fluid,

not shown. The upper branch of the four-way fitting 941s, normally closed by a pipeplug I03,

which maybe removed at suitable intervals-to effect lubrication of the moving parts of the servo-motor. V

To obtain the desired operating condition for theservo-motor, thereducing valve 88 is adjusted and set for the required pressure and the volume valve IOI is also adjusted and set for the requiredspeed of operation, and insofar as the last mentioned valve is concerned, it should be here carefully noted, that the volume regulating angle valve IN is not primarily a shut-off valve, inasmuch as another or second valve, not'shown, is providedin the: pressure fluid supply line I02 for shut-off purposes, hence, the valve IOI, of

necessity, after adjustment for the desired speed of operation should be left undisturbed, unless it is found necesary to increase or decrease the,

speed of operation, for any reason, at which time the volume valve IOI is re-adjusted and re-set to the new or selected speed of operation. In; the present disclosure, the volume angle. valve IN is shown and described as being connected to the inlet or high pressure side of the pressure reducing valve 89; however, it hasbeenfound desirable and expedient in many installations to transpose said volume angle valve IOI to the outlet or low pressure side of said pressure reducing valve 99; consequently, no restriction as to speciflclocation of these valves 99 and IM in relation to each other is contemplated by the present invention, the instant showing being.-

merely illustrative. I

In the electrical diagram illustrated in Fig. 13,; the numeral I04 designates a battery or other suitable source of electrical current or energy, while the numeral I05 designates the circuit of. said battery, one end orterminal of which is connected to the bridged inner terminals of the solenoid coils 85 and 06, as shown, the other or opposite end of said battery circuit I05 being branched, as indicated, and the indiv idual branches of ,same being each connected to corre spondi g p les r po nts of p nbuttcnstwqr,

10. and .11, it will be. noted and observed that the pole piece;.02,iin-j addition, also functions-as a closurefor :the. counterbore 62 adjacent thereto, while they point. maka: switches lfl'fi and 1 0L respectively;

To complete the circuits ot :the .;push= huttQn-.-:

sw itches'1- l B6 and. I131, a lead. ['08 connects-@the opposite pole or point of the switchJUBE-with the:

the cl'utch 'engagin' switchywhilefthe push but ton: switch. lill iuncti'ons as fthelclutch disen gaging switch; The vpush :button switches: 1:06 and. I O Iform and constitute. a clutchcontrolsta; tion; which may be located in clo'seproximity tor-.- the pressure fluid servo-motor 34,. or: remotely therefrom, -as' desired and. found expedient- However; 'should an' additional remote clutch: control stat-ion or stations be desired orrequireds the-battery circuit 105' may be es-tended, ias indicated'at' l05a, and' the push'button Circuits 108 and H19 -simil'arly extended; as indlcated'at-"l 0821 and I ll'9'z zyrespectively, to such stationor staw: ti'c'n's; not shown. 1 In the operation "of the two-way pressure fluid servo-motored, assuming the pressure reducingand -regulating valve same the volume or shut: ofi valve ['61 to he set andadjusted for'the desired operating condition, and also-assuming the servo mot'or 3'4 to be in the c1utch' disengaged position shown in Figs; l, 3 ahd l of the-drawings-,-= and the=fsolenoid .pist'on valve- 51' to be 'in itsl normally neutral position shown in Fig; 4, the operation'is a's fol-lows: To efiect'enga'gement of the clutch 3|, the operator closes or depresses the push button switch 106 to energize "the solenoid 0011 85 and thereby pull or axially inove the armature 87 and its. cor-related pistonv valve I 66' to the position shown in- Fig; 1'0,"whereupon pressure-fluid is admitted to the-left hand end of the power cylinder 38, through the related apertures 63 port lE'and passageways fig'thus causing-the piston '43 to move 'fro'rn ijts' position shown in fulllines to the position shownindotand d-a'sh lines in F'ig.*4,*and inconsequence' causing the clutch or? ntrellever-ta tdmioirlrdMthe fu l-1" line" position to the dot; and dash-' l-ine position showy-1 in Fig. 1' for eifetin'g engagement of the} clutch 3 l and concu r-rently' therewith exhausting the air in the right "hand endab f ower cili lliier 3 8', displaced hy the piston- Mi through the related *passageway E 5, -port tag-apertures 63' and exhaust port 6 5. nonc'ofrnpletion;-of1en-; gagemerit "of the clutch 'l, the on'eratorreleases' rnnusn button;s' -iteh 6-, ftherbyde-energiz *iblndidcoilfiE, fatwhich time; the coin-" pres'sedflpifston balancing spring Q92; at the solenoid end of the valve, returns' the piston valve 66 to'its-normal-1-y neutral positio'nishow i i Fig: 4, thus a-gain 'openi n'g both ends *of the pawer; cylinder $8 to the exhaust portsfifiand hermit-f ting exhaust of the ressuren 'd' n thle' lei-ti hand end of said cylinder through ts related exhaust port 65, as will be apparent by're ferring to'Fi-g' l. 1 I,

To 'efiect disengagement-tithe clutch '31; the operatorgcloses'or' depresses the'pu'sh Ebutton' switch 1-11? to energize t he solenoid coil "86 "and" thus pull or axially move the "armature" 81 and its correlated -pistonvalve -66--to-the' position show-n in Fig. 1-1, thereby admitting -'press'ure fiuid' to the -r ight-hand end offthepower cylinder- 38 and causing the piston {43 to return --to'- itsfull' liho positi'on shown imFig. 4 and-the clutclr w asmm sm:t amnqm mm; 511fOfI-h6l5613l09-3'R0t01? and thezservo-motqr.

the- :outer: terminal, inf the 20 they-like, equipped w Fig.1 1'. thus. dis ngaginetheq ut h' 31 d at he;

same, time exhausting, the air in the lefthand end. of. the power cylinder to the atmosphere throughits relatedexhaust rtti. Upon dis! 5;; engagement of, the clutch 3|, the operator releasesthe .pushahuttonlswitch I01, thus deenerizing the; solenoid coil; 86 --and thereby permit ting. the compressed piston balancingspring 92, at the outer or right hand end of the valve 51., to

returnable pis onva vefifi t s n neutral fluid-in theright hand-end oi the said cylinder is instantaneously exhausted to the atmosphere.

nrRef rr ne-now to. th t re -w y t pe-0f pre -1 inclusive, the numeral 130" designates the power.

takeeofi endi of..- an interna comb st o en n r a ouble-a n o r versing 0111170111431: h g a clutch-.shiftingor control. lever I32, to which is operatively and pivotally connected, at apoint intermediate its lengtnas by a. pivo pin -33. th e a W ,o-Pelectro-pheumatic shifting apparatus I34 of theJpresentfim/ention; I

Thenumeral 35 designates a pedestal or support; upon-the upper end of, which, the trunnion brackets I36 of the servo,.-motor [34 are mounted in opposed and ailigned spaced relation, and are fixedlysecuredj'theneto-bytstllds 0r bolts 1 31,; Mounted .ior oscillative moveme i t uni nion brackets: 136 is apneuma-ticpower cylinder I38 lhaving a 'bossed end cover J 93 fixed1y secured to its open end bar can screws 1 id cy i also' having' .axia1l .-.a1ignedtrurmions 1-4! in-.

tegrally formed. upon opposite sides thereof. for

mountinQthersarhein said trunnion brackets [36,150 compensate, f or the, arcuate path of travel .oif'the pivot ipin 1:33., as will lie-obvious by referrll'lg' toFig. 14. J 1

'axteriorly formed upon the top center portion o f the cylinder =1 at; substantially midway its length and extending, vertically therefrom is an i mtegral-rectangulan boss 1.42 terminating at its! upper endeln arectangular flan 143; Similarly formed upon 'said top scehterpozztiongand extend;- ing fromue'achend' of said rectangular :Ieossl-Q to each end ot-the cylinder: 138 -are longitudinally disposed semiecircular hollow rib's lM... I It should be understood here that the cylinder I38: Pismrovided with: gprssurcufllli passageway- M5 landzthe rectan ular. b oss 143 with -pre e fluidports .1 .1146 .wvith nared upp r -ends. M1. i the-'sameqmanner: for the samepurpose,

as hereinbefore. described for the cylinder -33 and rectangular boss 42. It should also be here understood, that the cylinder I38 is provided with--25 -piston of. the same. type as previously described :herein. for .the cylinder '38, the piston rod I 4 N o f which extends.:outwardlyz-thrqugh and- 'sis :gui'ded by the bOSSBd end cover I39.

and atits outer end is provided with a bifurcated.

member .:or woke till threadedly-secured:theretoand adapted'uto straddle the clutch or 00131501.

lever: l e": and to be zpivotally connected. thereto by vthe-qaivot'min 133-1. l

a 'Ihei three-away type :of servo motor: ]34.'is. ieq'uippe'di with substantially the same tyneefrsolenoid :Qr magnetically actuate piston valve. :51 .hereinbefore vdescribed for the semomdtor 341, hence Tlike numerals. designate like parts in Figs. 1 to 2 1,v inclusive, the slight difierentiation betweenthe solenoid Piston Eva-Ive- I34 being in the electricalv controls for same, which will hereinafter be more fully described.

' The piston valve 51, in the three-way type of outer face in alignment with theouter face of the pad 2I8, and fixedly secured to said pads, "as by cap screws 2I2, is one end of a longitudinally disposed plate bracket 2I3, said bracket for the" reason of compactness being soipositioned as to be co-extensive with theinner half of. the length of the power cylinder I38, as shown -3in the several views of the drawings. Integrally formed upon the outer face or-side of the bracket 2I3, in raligned spaced relation, are laterally extending perforated ears or lugs *2I4, and slidably mounted within said ears is a longitudinally disposed reciprocative cam rod 2I5 having a depressed or low portion 2I6 extending lengthwise of the same intermediate'its length and terminating in inclined or cam portions 2I.1, the function of which will presently be made apparent. The cam rod 2I5 is adapted to receive reciprocative movement from the piston rod I49, and for this purpose the common or corresponding ends of said cam and piston rods are adjustably interconnected by an arm or link 2I8, which is vadjustably secured to the piston rod I49 by'a hollow head set screw 2I9, and similarly secured to the cam rod by a hollow head set screw 2,20,for a reason hereinafter more fully set forth. I

Formed in endwise spaced relation, within that portion of the plate bracket 2I3 intermediate the ears 2I4, are longitudinally disposed slots 22I, and-mounted in endwise-spaced relation, for longitudinal adjustment upon the outer face of said slotted portion, are cam actuated, single pole, single throw, limit switches 222 and 223, respectively, which switches are secured or clamped in adjusted spaced relation upon the bracket 2I3 by clamping bolts 224, the inner end portions of which extend through the slots .22I for this purpose, as shown more clearly in Figs. 17 and 18.

In the electrical diagram for the three-way type of servo-motor I34, the numeral 225 designates a battery, or other source of electric current, and 226 denotes the circuit-of same, one

end, or terminal of which is connected to the bridgedinner terminals of the solenoid coils 85 and 86, while thetriple branches at the opposite end of said circuit 226 are connected to corresponding poles or points of push button, twopoint make, switches 221, 228 and 223, respectively. In order to complete the circuits of these, push button switches, the opposite pole or: point of fthe switch 221 is connectedby a 1'ead. 2 3 0 tothe outer terminal of the solenoid coil 85; the opposite pole or point of the switch 228 is jointlyconnected by a lead 23 I to common terminals "of the limit switches 222 and 223; and

'the opposite pole or point of the switch 229 is connected by a lead 232 to the outer terminal.

'of' the solenoid coil 86. The circuit of the limit switch 222 is completed by a bridge 'lead' 233, which connects the make and break terminal of said limit switch with the solenoid coil lead 230, while, the circuit of the limit switch 223 is co'mpleted'by a bridge lead 23'4Qwhich connects form and constitute a clutch control station,-

which may be located in close proximity to the three-way pressure fluid servo-motor I34, erremotely therefrom, as found necessary and expedient. In the event an additional 1 remote clutch control; station or stations be required, the battery circuit 226 is extended, as indicated at 226a, and the push buttoncircuits 230; 231

and 232 are similarly extended, as indicated ;at

238a, 23m and 232a, to such control station'or stations, not shown.

The primary function and purpose, in the three-way pressure fluid servo-motor I34, ofthe adjustable'cam rod 2I-5 andthe adjustablelimit switches-222 and 223. operated thereby, isgto provide an adjustable neutral position or-positive stop for said servo-motor, inasmuch asaxial or longitudinal adjustmentof the cam rod 2L5, in its correlated adjustable arm 2I8, willvary the location of the neutral positionor-positive stop of the servo-motor in relation tothe total stroke of the same," as will be readily, apparent by referring to I the drawings; In connection with the foregoing, another important feature and function of the adjustable limit switches 222 and 223 carried by the bracket 2I3, is, that such switches are longitudinally adjusted and set relative to each other to conform with any selected operational speed of the servo-motor In the present application ofithe servo-motor I34 tothe clutch I3I, the aforementioned neutral position orpositive stop of said servo-motor represents the disengaged position of said clutch, it being here noted in this connection, that when the servo-motor I34 is in the neutral position aforesaid, the circuits of the limit switches 222 and 223 are open and, in consequence, the push button switch 228' is inoperative. Howeverp it should also be noted'at this point that the circuits of the push button switches 221' 'andw229 are entirely independent of the limit switch circuits, and, hence, are operative at all times upon depression or closure 'of said button switches, regardless of whether the servo-motor I34 is in either terminal position or in its intermediate neutral position. In other words,"the servo-motor may be moved from its neuti'al'position to its forward clutch engaged position, .or'

to its reverse clutch engaged position, or from the latter to the forward position, orvice-versa, by merely depressing or closing the appropriate push button switch 221 or 229. As abovestated,

the cam rod H and the resilient finger of the switch 223 is resting upon the lower level or portion 2 Iii'of said'camrod, see Figs. 14 and 19. However, when the servo-motor I34 is in a forward clutch engaged position, the limit switch 222 is open and the limit switch 223 is closed, for the reason that the resilient fingers of both such switches are resting upon the higher level "of the cam rod 2l5, seeFig 20'. On the other hand, whenthe servo-motor I34 is in a reverse clutch engaged position, the limit switch 222is closed and the limit switch 223 is open, since the resilient fingers of both these switches are resting upon the lower level or portion 2I6 of thecam rod 2'I5, see Figs. 16, 17 and 21.

be positively actuated by the high point of the 5 cam," thus it will be apparent and obvious from theioregoing that the limit switch 222 is opened "when its finger rides up on the cam and the limit 'switch223 is closed when its finger rides up on the cam; in other words, the action of these limit switches'are opposite to each other when their fingers move up and down. "The" operation of the three-way pressure fluid servs-motor I34 is substantially the same as thathreinbeforedescribed for the two-way pressure fiui'd servo-motor 34, insofar as full travel or-shifting movement of the. servo-motor is concerned, the primary and essential difi'erence in the operation being the actuation and' functi'oning of the limit switches 222 and 223' together with their correlated push button switch 228,

whereby partial travelor limited movement of 'the's'ervo-motor is obtained; With the foregoing in view and assuming the servo-motor. I34 to "be 'i'n the'neutral position shown in full lines, in Fig; I4 and the limit switches 222' and. 223 open, as- 'shown" in Fig. 19, the operator, if forward movment'is desired, closes or'depresses the push button switch 221 to energize the solenoid coil 85 andthus effect forward engagement of'the clutch I3I, as shown by dot and dash lines "in Figs. 14 and '16, at which time; see Fig. 20; the limit switch 222 is open and the limit switch 223 is closed; if, however, reverse movement is desired the operator closes or depresses the push button switch 229 to energize the solenoid coil 86 and thus efi'ect reverse engagement of the clutch I3I, as shown by double dot and dash lines in Fig; 14 andfull lines in Fig. 16, at which time, see Figs. 16, 17 and 2-1,, the limit switch'222 is, closed and the limit switch 223 is open. To

returnv to the neutral position from either forward orireverse clutch engaged positions, the operator closes or depresses the push. button switchi22B; and if movement is fromthe forward position, the solenoid coil 86 is energized through u-the'elosedi limitswitch 223, but, if movement is from' the reverse position the solenoid coil 85 vis. energized through the closed'limit switch 222. .Manifestly, by varying the location and-number of cam portions on the cam rod 2I5, and increasing the number of limit and push button switches; shifting movements of varying numbers and lengths may be obtained or provided 7 for the servo-motor I34. 1

In the accompanying drawings and in the foregoing description, thetrunnions'. 4i and MI, respectively, of the'power cylinders 38 and. I38 have been shown and described, as located slightly to the right of the mid-lengths of the same, this, for the purpose ofmore uniformly distributing and balancing the weight of the servo,- motors 34 and I34 upon and about their respective correlated trunnions insofar as practicable, and thereby relieve their respective correlated clutch shifting levers 32.. or I32 of any unnecessary load.

In the present disclosure, a power cylinder 38 has been shown and described for the two-way servo-motor 34, and, another power cylinder I38 for the three-way servo-motor I34; howeven'in order to minimize; or reduce cost. of manufacture of each type of'unit, it. should be here'stated that the power cylinder I 38:"inay be. used for both the two-way and threesway types 'ofservomotors.

In the initial adjustment and setting, also, in any readjustment and resetting of the, pressure fluid reducing and regulating valve 9i!v and the volume regulating angle valve II of the threeway servo-motor I34, great care should be exercised and observed in eifecting the same, principally for the reason that excessive. pressure and volume will cause and produce undesirable hunting of the servo-motor in seeking its. neutral position.

From the foregoing, it will be apparent and manifest that the servo-motors herein disclosed are comparatively simple in construction and operation, are easy to install, and do not require any special skill or qualification on the part of the operator of the same;

While I have herein shown and described the invention with sufficient detail to enable those skilled in the art to understand the mode of construction and the principles involved, it is to be understood that there is no intentional limitation herein to the specific forms and precise details of construction of the invention shown and described, except as expressly defined by the appended claims, and it is to be further understood that various modifications of such construction may be resorted to without departing from the spirit of the invention, or the benefits derivable therefrom.

What I claim as my invention, and desire to secure by Letters Patent, is:

1. In a pressure fluid servo-motor, the combination of pressure fluid actuated power means having two operating, positions and an intermediate adjustable neutral position; valve means for controlling ingress and egress of pressure fluid to and from said powermeans; and. means for actuating said valve means whereby the power means is selectively moved from its neutral position to either of its operating positions or from one of the latter to the other and viceversa, said valve actuating means including means operable by and adjustable relative .tosaid power means for changing the neutral position of the latter relative to the operating positions of the same, said actuating means also. including control units mounted upon said power means for individualfladjustment. relative to each other soas to co-act with and be operable by. said neutral position changing means for effecting stoppage of the power means in any selected neutral position.v

2. In a pressure fluid servo-motor, the combination of pressure fluid actuated power means having two operating positions and an interme- 13 diate adjustable neutral position; electricallyoperable and pressure-balanced-valve means; for controlling ingress and egress of; pressure fluid to and from said power means; manually operable switch means for actuating said valve means whereby the power means is selectively moved from its neutral position to either of its operating positions or from one of the latter to the other andv vice-versa; power operated "switch means for stopping said power means in its adjusted neutral position, said switch means including switches mounted upon said power means for individual adjustment relative thereto and to each other, and means operatively connected to said power means for actuating said switches, said last mentioned means being adjustable relative to the power means for selectively determining and regulating the neutral position of the latter.

3. In a pressure fluid servo-motor, the combination of pressure fluid actuated power means having two operating positions and an intermediate adjustable neutral position; electrically operable and pressure-balanced valve means for controlling ingress and egress of pressure fluid to and from said power means; manually operable switch means for actuating said valve means whereby the power means is moved selectively from its neutral position to either of its operating positions or from one of the latter to the other and vice-versa; power operated limit switches for stopping said power means in its selectively adjusted neutral position, said limit switches being mounted upon said power means for individual adjustment relative thereto and to each other; and a cam member operatively connected to the power means for actuating said limit switches, said cam member being adjustable relative to said power means for selectively determining and regulating the neutral position of the latter.

4. In a pressure fluid servo-motor, the combination of pressure fluid actuated power means having two operating positions and an intermediate adjustable neutral position; electrically operable and pressure balanced valve means for controlling ingress and egress of pressure fluid to and from. said power means; manually operable switch means for actuating said valve means whereby the power means is selectively moved from its neutral position to either of its operating positions or from one of the latter to the other and vice-versa; power operated limit switches for stopping said power means in its selected neutral position, said limit switches being adjustable relative to each other for varying the operational speed of the power means; and means adjustably interconnected to and moving synchronously with said power means for actuating said limit switches and for selectively adjusting the neutral position of said power means.

5. The combination with a reversible power transmission mechanism provided with a manually and power operated shift lever having an adjustable neutral position, of a pressure fluid servo-motor comprising a fluid pressure power cylinder; a reciprocating piston therein having a piston rod extending therefrom for operative connection with said shift lever; a pressure and spring-balanced solenoid operated valve communicating with the ends of said power cylinder for controlling ingress and egress of pressure fluid thereto and therefrom; manually operable switch means for activating-the solenoid of said valve; power operated switches for stopping said shift lever in any selected neutral position, said I said .means being adjustable relative to said pissiton rod whereby the neutralv position of the shift .lever' aforesaid may be changed to vary; the de- -greef'of :throw of .samef-upon each side of its selected neutral position.

6. The combination with a reversible power transmission mechanism provided with a manually and power operated shift lever having an adjustable neutral position, of a pressure fluid servo-motor comprising a trunnion mounted oscillative pneumatic power cylinder having its trunnion axes located a point intermediate the length thereof so that the servo-motor as a unit is substantially in balance when said shift lever is in its neutral position; a reciprocable piston in said cylinder having a piston rod extending therefrom for pivotal connection with said shift lever; a pressure and spring-balanced solenoid operated valve communicating with the. ends of said power cylinder for controlling ingress and egress of pressure fluid thereto and therefrom; manually operable switch means for activating the solenoid of said valve; power operated limit switches for stopping said shift lever in any selected neutral position, said limit switches being mounted upon said power cylinder for individual adjustment relative to the center of same and to each other; and a limit switch activating cam member operatively connected to the aforesaid reciprocable piston rod for synchronous movement therewith, said cam member being adjustable relative to said piston rod for varying the degree of throw of the shift lever on each side of any selected neutral position of the same.

7. The combination with a reversible power transmission mechanism provided with a menually and power operated shift lever having two operating positions and an adjustable neutral position, of a pressure fluid servo-motor for said shift lever and comprising a fluid pressure power cylinder; a piston reciprocable therein having a piston rod extending therefrom for operative connection with said shift lever; a solenoid valve communicating with the ends of said power cylinder for controlling ingress and egress of pres sure fluid thereto and therefrom; manually operable switch means for activating the solenoid of said valve, including individual switches for independently obtaining movements of said shift lever from its neutral position to either operating positions or from one of the latter to the other and vice-versa; independently adjustable power operated limit switches for stopping the shift lever in any selected neutral position and adaptable upon independent adjustment relative to each other to conform with the operational speed of the servo-motor; and a limit switch operating cam rod disposed in spaced parallel and substantially co-extensive relation to said piston rod and adjustable secured thereto at a common end for synchronous movement therewith, said cam rod being adjustable relative to the piston rod for varying the degree of throw of the shift lever on each side of its selected neutral position.

GEORGE G. NAUD.

(References on following page) 15 REFERENQES CITED Number The fc'flirzivi ing references are of record in the 4 man: this patent: 0 2332-938 0. i V r 2,234,019 UNITED STATES PATENTS 2314 444 Number Name Date 5 ,8

"1523.0,1'50 Geraghty June 19, 191 7 1,456,050 'Benbow .May 22, 1923 2,030,986 Havill Feb. "18, 1936 P 2,094,153 Harrington Sept. 28,1937 10 515,617

Kliesrath Apr. 25, 1939 Name Date Baade Mar. 26,1940 Stone Feb. 18, 1941 Bragg M514, 1941 Crittenden Max:223, 1943 Lane July 18, 1944 FOREIGN PATENTS Country Date Great Britain Dec. 11.; 1939 

